Electrodeless inductively-coupled fluorescent lamps (ICFL) have longer life than conventional fluorescent lamps that employ hot cathodes. The plasma which radiates visible and UV light is generated in the lamp by an azimuthal electric field, E.sub.ind, induced in the envelope by an induction coil. The coil is a critical component in the operation and performance of such lamps. This invention is about a particular design aspect of such a coil.